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<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2014 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: NavigableSets.html 842 2015-03-07 18:20:42Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.jsimpledb.util;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>import java.util.Arrays;<a name="line.10"></a>
<span class="sourceLineNo">011</span>import java.util.Collections;<a name="line.11"></a>
<span class="sourceLineNo">012</span>import java.util.Comparator;<a name="line.12"></a>
<span class="sourceLineNo">013</span>import java.util.NavigableSet;<a name="line.13"></a>
<span class="sourceLineNo">014</span><a name="line.14"></a>
<span class="sourceLineNo">015</span>/**<a name="line.15"></a>
<span class="sourceLineNo">016</span> * Utility methods relating to {@link NavigableSet}.<a name="line.16"></a>
<span class="sourceLineNo">017</span> */<a name="line.17"></a>
<span class="sourceLineNo">018</span>public final class NavigableSets {<a name="line.18"></a>
<span class="sourceLineNo">019</span><a name="line.19"></a>
<span class="sourceLineNo">020</span>    private NavigableSets() {<a name="line.20"></a>
<span class="sourceLineNo">021</span>    }<a name="line.21"></a>
<span class="sourceLineNo">022</span><a name="line.22"></a>
<span class="sourceLineNo">023</span>    /**<a name="line.23"></a>
<span class="sourceLineNo">024</span>     * Create a read-only view of the intersection of two or more {@link NavigableSet}s that have a consistent sort order.<a name="line.24"></a>
<span class="sourceLineNo">025</span>     * The {@linkplain NavigableSet#comparator Comparator}s of the sets must all be {@linkplain Comparator#equals equal}<a name="line.25"></a>
<span class="sourceLineNo">026</span>     * (or else all null, for natural ordering).<a name="line.26"></a>
<span class="sourceLineNo">027</span>     *<a name="line.27"></a>
<span class="sourceLineNo">028</span>     * &lt;p&gt;<a name="line.28"></a>
<span class="sourceLineNo">029</span>     * The returned intersection interates efficiently: a complete iteration requires &lt;i&gt;O(N * M)&lt;/i&gt; queries, where<a name="line.29"></a>
<span class="sourceLineNo">030</span>     * &lt;i&gt;N&lt;/i&gt; is the size of the smallest set, and &lt;i&gt;M&lt;/i&gt; is the number of sets.<a name="line.30"></a>
<span class="sourceLineNo">031</span>     * &lt;/p&gt;<a name="line.31"></a>
<span class="sourceLineNo">032</span>     *<a name="line.32"></a>
<span class="sourceLineNo">033</span>     * @param sets the sets to intersect<a name="line.33"></a>
<span class="sourceLineNo">034</span>     * @param &lt;E&gt; element type<a name="line.34"></a>
<span class="sourceLineNo">035</span>     * @return the intersection of all {@code sets}<a name="line.35"></a>
<span class="sourceLineNo">036</span>     * @throws IllegalArgumentException if the {@code sets} do not have equal {@link Comparator}s<a name="line.36"></a>
<span class="sourceLineNo">037</span>     */<a name="line.37"></a>
<span class="sourceLineNo">038</span>    public static &lt;E&gt; NavigableSet&lt;E&gt; intersection(Iterable&lt;? extends NavigableSet&lt;E&gt;&gt; sets) {<a name="line.38"></a>
<span class="sourceLineNo">039</span>        return new IntersectionNavigableSet&lt;E&gt;(sets);<a name="line.39"></a>
<span class="sourceLineNo">040</span>    }<a name="line.40"></a>
<span class="sourceLineNo">041</span><a name="line.41"></a>
<span class="sourceLineNo">042</span>    /**<a name="line.42"></a>
<span class="sourceLineNo">043</span>     * Create a read-only view of the intersection of two or more {@link NavigableSet}s that have a consistent sort order.<a name="line.43"></a>
<span class="sourceLineNo">044</span>     * The {@linkplain NavigableSet#comparator Comparator}s of the sets must all be {@linkplain Comparator#equals equal}<a name="line.44"></a>
<span class="sourceLineNo">045</span>     * (or else all null, for natural ordering).<a name="line.45"></a>
<span class="sourceLineNo">046</span>     *<a name="line.46"></a>
<span class="sourceLineNo">047</span>     * &lt;p&gt;<a name="line.47"></a>
<span class="sourceLineNo">048</span>     * The returned intersection interates efficiently: a complete iteration takes time &lt;i&gt;O(N * M)&lt;/i&gt; where<a name="line.48"></a>
<span class="sourceLineNo">049</span>     * &lt;i&gt;N&lt;/i&gt; is the size of the smallest set, and &lt;i&gt;M&lt;/i&gt; is the number of sets.<a name="line.49"></a>
<span class="sourceLineNo">050</span>     * &lt;/p&gt;<a name="line.50"></a>
<span class="sourceLineNo">051</span>     *<a name="line.51"></a>
<span class="sourceLineNo">052</span>     * @param sets the sets to intersect<a name="line.52"></a>
<span class="sourceLineNo">053</span>     * @param &lt;E&gt; element type<a name="line.53"></a>
<span class="sourceLineNo">054</span>     * @return the intersection of all {@code sets}<a name="line.54"></a>
<span class="sourceLineNo">055</span>     * @throws IllegalArgumentException if the {@code sets} do not have equal {@link Comparator}s<a name="line.55"></a>
<span class="sourceLineNo">056</span>     */<a name="line.56"></a>
<span class="sourceLineNo">057</span>    @SafeVarargs<a name="line.57"></a>
<span class="sourceLineNo">058</span>    @SuppressWarnings("varargs")<a name="line.58"></a>
<span class="sourceLineNo">059</span>    public static &lt;E&gt; NavigableSet&lt;E&gt; intersection(NavigableSet&lt;E&gt;... sets) {<a name="line.59"></a>
<span class="sourceLineNo">060</span>        return new IntersectionNavigableSet&lt;E&gt;(Arrays.asList(sets));<a name="line.60"></a>
<span class="sourceLineNo">061</span>    }<a name="line.61"></a>
<span class="sourceLineNo">062</span><a name="line.62"></a>
<span class="sourceLineNo">063</span>    /**<a name="line.63"></a>
<span class="sourceLineNo">064</span>     * Create a read-only view of the union of two or more {@link NavigableSet}s that have a consistent sort order.<a name="line.64"></a>
<span class="sourceLineNo">065</span>     * The {@linkplain NavigableSet#comparator Comparator}s of the sets must all be {@linkplain Comparator#equals equal}<a name="line.65"></a>
<span class="sourceLineNo">066</span>     * (or else all null, for natural ordering).<a name="line.66"></a>
<span class="sourceLineNo">067</span>     *<a name="line.67"></a>
<span class="sourceLineNo">068</span>     * @param sets the sets to union<a name="line.68"></a>
<span class="sourceLineNo">069</span>     * @param &lt;E&gt; element type<a name="line.69"></a>
<span class="sourceLineNo">070</span>     * @return the union of all {@code sets}<a name="line.70"></a>
<span class="sourceLineNo">071</span>     * @throws IllegalArgumentException if the {@code sets} do not have equal {@link Comparator}s<a name="line.71"></a>
<span class="sourceLineNo">072</span>     */<a name="line.72"></a>
<span class="sourceLineNo">073</span>    @SafeVarargs<a name="line.73"></a>
<span class="sourceLineNo">074</span>    @SuppressWarnings("varargs")<a name="line.74"></a>
<span class="sourceLineNo">075</span>    public static &lt;E&gt; NavigableSet&lt;E&gt; union(NavigableSet&lt;E&gt;... sets) {<a name="line.75"></a>
<span class="sourceLineNo">076</span>        return new UnionNavigableSet&lt;E&gt;(Arrays.asList(sets));<a name="line.76"></a>
<span class="sourceLineNo">077</span>    }<a name="line.77"></a>
<span class="sourceLineNo">078</span><a name="line.78"></a>
<span class="sourceLineNo">079</span>    /**<a name="line.79"></a>
<span class="sourceLineNo">080</span>     * Create a read-only view of the union of two or more {@link NavigableSet}s that have a consistent sort order.<a name="line.80"></a>
<span class="sourceLineNo">081</span>     * The {@linkplain NavigableSet#comparator Comparator}s of the sets must all be {@linkplain Comparator#equals equal}<a name="line.81"></a>
<span class="sourceLineNo">082</span>     * (or else all null, for natural ordering).<a name="line.82"></a>
<span class="sourceLineNo">083</span>     *<a name="line.83"></a>
<span class="sourceLineNo">084</span>     * @param sets the sets to union<a name="line.84"></a>
<span class="sourceLineNo">085</span>     * @param &lt;E&gt; element type<a name="line.85"></a>
<span class="sourceLineNo">086</span>     * @return the union of all {@code sets}<a name="line.86"></a>
<span class="sourceLineNo">087</span>     * @throws IllegalArgumentException if the {@code sets} do not have equal {@link Comparator}s<a name="line.87"></a>
<span class="sourceLineNo">088</span>     */<a name="line.88"></a>
<span class="sourceLineNo">089</span>    public static &lt;E&gt; NavigableSet&lt;E&gt; union(Iterable&lt;? extends NavigableSet&lt;E&gt;&gt; sets) {<a name="line.89"></a>
<span class="sourceLineNo">090</span>        return new UnionNavigableSet&lt;E&gt;(sets);<a name="line.90"></a>
<span class="sourceLineNo">091</span>    }<a name="line.91"></a>
<span class="sourceLineNo">092</span><a name="line.92"></a>
<span class="sourceLineNo">093</span>    /**<a name="line.93"></a>
<span class="sourceLineNo">094</span>     * Create a read-only view of the difference of two {@link NavigableSet}s that have a consistent sort order.<a name="line.94"></a>
<span class="sourceLineNo">095</span>     * That is, a set containing all elements contained in the first set but not the second.<a name="line.95"></a>
<span class="sourceLineNo">096</span>     * The {@linkplain NavigableSet#comparator Comparator}s of the sets must all be {@linkplain Comparator#equals equal}<a name="line.96"></a>
<span class="sourceLineNo">097</span>     * (or else all null, for natural ordering).<a name="line.97"></a>
<span class="sourceLineNo">098</span>     *<a name="line.98"></a>
<span class="sourceLineNo">099</span>     * @param set1 original set<a name="line.99"></a>
<span class="sourceLineNo">100</span>     * @param set2 set of elements to exclude from {@code set1}<a name="line.100"></a>
<span class="sourceLineNo">101</span>     * @param &lt;E&gt; element type<a name="line.101"></a>
<span class="sourceLineNo">102</span>     * @return the difference of {@code set1} and {@code set2}<a name="line.102"></a>
<span class="sourceLineNo">103</span>     * @throws IllegalArgumentException if the {@code set1} and {@code set2} do not have equal {@link Comparator}s<a name="line.103"></a>
<span class="sourceLineNo">104</span>     */<a name="line.104"></a>
<span class="sourceLineNo">105</span>    public static &lt;E&gt; NavigableSet&lt;E&gt; difference(NavigableSet&lt;E&gt; set1, NavigableSet&lt;E&gt; set2) {<a name="line.105"></a>
<span class="sourceLineNo">106</span>        return new DifferenceNavigableSet&lt;E&gt;(set1, set2);<a name="line.106"></a>
<span class="sourceLineNo">107</span>    }<a name="line.107"></a>
<span class="sourceLineNo">108</span><a name="line.108"></a>
<span class="sourceLineNo">109</span>    /**<a name="line.109"></a>
<span class="sourceLineNo">110</span>     * Create a read-only view of the symmetric difference of two {@link NavigableSet}s that have a consistent sort order.<a name="line.110"></a>
<span class="sourceLineNo">111</span>     * That is, the set containing all elements contained in the first set or the second set, but not in both sets.<a name="line.111"></a>
<span class="sourceLineNo">112</span>     * The {@linkplain NavigableSet#comparator Comparator}s of the sets must all be {@linkplain Comparator#equals equal}<a name="line.112"></a>
<span class="sourceLineNo">113</span>     * (or else all null, for natural ordering).<a name="line.113"></a>
<span class="sourceLineNo">114</span>     *<a name="line.114"></a>
<span class="sourceLineNo">115</span>     * @param set1 first set<a name="line.115"></a>
<span class="sourceLineNo">116</span>     * @param set2 second set<a name="line.116"></a>
<span class="sourceLineNo">117</span>     * @param &lt;E&gt; element type<a name="line.117"></a>
<span class="sourceLineNo">118</span>     * @return the symmetric difference of {@code set1} and {@code set2}<a name="line.118"></a>
<span class="sourceLineNo">119</span>     * @throws IllegalArgumentException if the {@code set1} and {@code set2} do not have equal {@link Comparator}s<a name="line.119"></a>
<span class="sourceLineNo">120</span>     */<a name="line.120"></a>
<span class="sourceLineNo">121</span>    public static &lt;E&gt; NavigableSet&lt;E&gt; symmetricDifference(NavigableSet&lt;E&gt; set1, NavigableSet&lt;E&gt; set2) {<a name="line.121"></a>
<span class="sourceLineNo">122</span>        return NavigableSets.difference(NavigableSets.union(set1, set2), NavigableSets.intersection(set1, set2));<a name="line.122"></a>
<span class="sourceLineNo">123</span>    }<a name="line.123"></a>
<span class="sourceLineNo">124</span><a name="line.124"></a>
<span class="sourceLineNo">125</span>    /**<a name="line.125"></a>
<span class="sourceLineNo">126</span>     * Create a {@link NavigableSet} containing a single element and natural ordering.<a name="line.126"></a>
<span class="sourceLineNo">127</span>     *<a name="line.127"></a>
<span class="sourceLineNo">128</span>     * @param value singleton value<a name="line.128"></a>
<span class="sourceLineNo">129</span>     * @param &lt;E&gt; element type<a name="line.129"></a>
<span class="sourceLineNo">130</span>     * @return singleton set<a name="line.130"></a>
<span class="sourceLineNo">131</span>     * @throws IllegalArgumentException if {@code value} is null or<a name="line.131"></a>
<span class="sourceLineNo">132</span>     *  {@code value}'s class has no natural ordering (i.e., does not implement {@link Comparable})<a name="line.132"></a>
<span class="sourceLineNo">133</span>     */<a name="line.133"></a>
<span class="sourceLineNo">134</span>    public static &lt;E&gt; NavigableSet&lt;E&gt; singleton(E value) {<a name="line.134"></a>
<span class="sourceLineNo">135</span>        return NavigableSets.&lt;E&gt;singleton(null, value);<a name="line.135"></a>
<span class="sourceLineNo">136</span>    }<a name="line.136"></a>
<span class="sourceLineNo">137</span><a name="line.137"></a>
<span class="sourceLineNo">138</span>    /**<a name="line.138"></a>
<span class="sourceLineNo">139</span>     * Create a {@link NavigableSet} containing a single element.<a name="line.139"></a>
<span class="sourceLineNo">140</span>     *<a name="line.140"></a>
<span class="sourceLineNo">141</span>     * @param comparator comparator, or null for natural ordering<a name="line.141"></a>
<span class="sourceLineNo">142</span>     * @param value singleton value (possibly null)<a name="line.142"></a>
<span class="sourceLineNo">143</span>     * @param &lt;E&gt; element type<a name="line.143"></a>
<span class="sourceLineNo">144</span>     * @return singleton set<a name="line.144"></a>
<span class="sourceLineNo">145</span>     * @throws IllegalArgumentException if {@code comparator} is null and either {@code value} is null or<a name="line.145"></a>
<span class="sourceLineNo">146</span>     *  {@code value}'s class has no natural ordering (i.e., does not implement {@link Comparable})<a name="line.146"></a>
<span class="sourceLineNo">147</span>     */<a name="line.147"></a>
<span class="sourceLineNo">148</span>    public static &lt;E&gt; NavigableSet&lt;E&gt; singleton(Comparator&lt;? super E&gt; comparator, E value) {<a name="line.148"></a>
<span class="sourceLineNo">149</span>        return new SingletonNavigableSet&lt;E&gt;(comparator, value);<a name="line.149"></a>
<span class="sourceLineNo">150</span>    }<a name="line.150"></a>
<span class="sourceLineNo">151</span><a name="line.151"></a>
<span class="sourceLineNo">152</span>    /**<a name="line.152"></a>
<span class="sourceLineNo">153</span>     * Create an empty {@link NavigableSet}.<a name="line.153"></a>
<span class="sourceLineNo">154</span>     * The returned set's {@link NavigableSet#comparator comparator()} method will return null.<a name="line.154"></a>
<span class="sourceLineNo">155</span>     *<a name="line.155"></a>
<span class="sourceLineNo">156</span>     * @param &lt;E&gt; element type<a name="line.156"></a>
<span class="sourceLineNo">157</span>     * @return empty set<a name="line.157"></a>
<span class="sourceLineNo">158</span>     */<a name="line.158"></a>
<span class="sourceLineNo">159</span>    public static &lt;E&gt; NavigableSet&lt;E&gt; empty() {<a name="line.159"></a>
<span class="sourceLineNo">160</span>        return NavigableSets.&lt;E&gt;empty(null);<a name="line.160"></a>
<span class="sourceLineNo">161</span>    }<a name="line.161"></a>
<span class="sourceLineNo">162</span><a name="line.162"></a>
<span class="sourceLineNo">163</span>    /**<a name="line.163"></a>
<span class="sourceLineNo">164</span>     * Create an empty {@link NavigableSet} with a specified {@link Comparator}.<a name="line.164"></a>
<span class="sourceLineNo">165</span>     *<a name="line.165"></a>
<span class="sourceLineNo">166</span>     * @param comparator comparator, or null for natural ordering<a name="line.166"></a>
<span class="sourceLineNo">167</span>     * @param &lt;E&gt; element type<a name="line.167"></a>
<span class="sourceLineNo">168</span>     * @return empty set<a name="line.168"></a>
<span class="sourceLineNo">169</span>     */<a name="line.169"></a>
<span class="sourceLineNo">170</span>    public static &lt;E&gt; NavigableSet&lt;E&gt; empty(Comparator&lt;? super E&gt; comparator) {<a name="line.170"></a>
<span class="sourceLineNo">171</span>        return new EmptyNavigableSet&lt;E&gt;(comparator);<a name="line.171"></a>
<span class="sourceLineNo">172</span>    }<a name="line.172"></a>
<span class="sourceLineNo">173</span><a name="line.173"></a>
<span class="sourceLineNo">174</span>    /**<a name="line.174"></a>
<span class="sourceLineNo">175</span>     * Get a non-null {@link Comparator} that sorts consistently with, and optionally reversed from, the given {@link Comparator}.<a name="line.175"></a>
<span class="sourceLineNo">176</span>     *<a name="line.176"></a>
<span class="sourceLineNo">177</span>     * @param comparator comparator, or null for natural ordering<a name="line.177"></a>
<span class="sourceLineNo">178</span>     * @param reversed whether to return a reversed {@link Comparator}<a name="line.178"></a>
<span class="sourceLineNo">179</span>     * @param &lt;T&gt; compared type<a name="line.179"></a>
<span class="sourceLineNo">180</span>     * @return a non-null {@link Comparator}<a name="line.180"></a>
<span class="sourceLineNo">181</span>     */<a name="line.181"></a>
<span class="sourceLineNo">182</span>    static &lt;T&gt; Comparator&lt;T&gt; getComparator(Comparator&lt;T&gt; comparator, boolean reversed) {<a name="line.182"></a>
<span class="sourceLineNo">183</span>        return comparator != null ?<a name="line.183"></a>
<span class="sourceLineNo">184</span>          (reversed ? Collections.&lt;T&gt;reverseOrder(comparator) : comparator) :<a name="line.184"></a>
<span class="sourceLineNo">185</span>          (reversed ? Collections.&lt;T&gt;reverseOrder() : new NaturalComparator&lt;T&gt;());<a name="line.185"></a>
<span class="sourceLineNo">186</span>    }<a name="line.186"></a>
<span class="sourceLineNo">187</span><a name="line.187"></a>
<span class="sourceLineNo">188</span>// NaturalComparator<a name="line.188"></a>
<span class="sourceLineNo">189</span><a name="line.189"></a>
<span class="sourceLineNo">190</span>    private static class NaturalComparator&lt;T&gt; implements Comparator&lt;T&gt; {<a name="line.190"></a>
<span class="sourceLineNo">191</span><a name="line.191"></a>
<span class="sourceLineNo">192</span>        @Override<a name="line.192"></a>
<span class="sourceLineNo">193</span>        @SuppressWarnings("unchecked")<a name="line.193"></a>
<span class="sourceLineNo">194</span>        public int compare(T e1, T e2) {<a name="line.194"></a>
<span class="sourceLineNo">195</span>            return ((Comparable&lt;T&gt;)e1).compareTo(e2);<a name="line.195"></a>
<span class="sourceLineNo">196</span>        }<a name="line.196"></a>
<span class="sourceLineNo">197</span>    }<a name="line.197"></a>
<span class="sourceLineNo">198</span>}<a name="line.198"></a>
<span class="sourceLineNo">199</span><a name="line.199"></a>




























































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